scholarly journals Constitutive Expression of Arabidopsis Senescence Associated Gene 101 in Brachypodium distachyon Enhances Resistance to Puccinia brachypodii and Magnaporthe oryzae

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1316
Author(s):  
Ning Wang ◽  
Na Song ◽  
Zejun Tang ◽  
Xiaojie Wang ◽  
Zhensheng Kang ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Magnaporthe Oryzae ◽  
Plant Immunity ◽  
Brachypodium Distachyon ◽  
Constitutive Expression ◽  
Wild Type ◽  
Homologous Genes ◽  
Pathogenesis Related ◽  
Salicylic Acid Accumulation ◽  
Pathogenesis Related Gene

Brachypodium distachyon, as an effective model of cereal grains, is susceptible to most destructive cereal pathogens. Senescence associated gene 101 (SAG101) has been studied extensively in Arabidopsis. SAG101 is one of the important regulators of plant immunity. However, no homologous genes of AtSAG101 were found in B. distachyon. In this study, the AtSAG101 gene was transformed into B. distachyon. Three transgenic plant lines containing the AtSAG101 gene were confirmed by PCR and GUS gene activity. There were fewer Puccinia brachypodii urediospores in the AtSAG101-overexpressing plants compared to wild type plants. P. brachypodii biomass was obviously decreased in AtSAG101 transgenic plants. The length of infection hyphae and infection unit areas of P. brachypodii were significantly limited in transgenic plants. Moreover, there were small lesions in AtSAG101 transgenic plants challenged by Magnaporthe oryzae. Salicylic acid accumulation was significantly increased, which led to elevated pathogenesis-related gene expression in transgenic B. distachyon inoculated by P. brachypodii or M. oryzae compared to wild type plants. These results were consistent with infected phenotypes. Overexpression of AtSAG101 in B. distachyon caused resistance to M. oryzae and P. brachypodii. These results suggest that AtSAG101 could regulate plant resistance in B. distachyon.

scholarly journals Isolate specific responses of the non-host grass Brachypodium distachyon to the fungal pathogen Zymoseptoria tritici, compared to wheat.

2020 ◽  
Author(s):  
Ailsing Reilly ◽  
Sujit Jung Karki ◽  
Anthony Twamley ◽  
Anna M.M Tiley ◽  
Steven Kildea ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Plant Immunity ◽  
Brachypodium Distachyon ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Pr Genes ◽  
Zymoseptoria Tritici ◽  
Expression Of Genes ◽  
Pathogenesis Related ◽  
Defence Gene Expression

Septoria tritici blotch (STB) is an important foliar disease of wheat that is caused by the fungal pathogen Zymoseptoria tritici. The grass Brachypodium distachyon has been used previously as a model system for cereal-pathogen interactions. In this study, we examined the non-host resistance (NHR) response of B. distachyon to two different Z. tritici isolates in comparison to wheat. These isolates vary in aggressiveness on wheat cv. Remus displaying significant differences in disease and pycnidia coverage. Using microscopy, we found that similar isolate specific responses were observed for H2O2 accumulation and cell death in both wheat and B. distachyon. Despite this, induction of isolate specific patterns of defence gene expression by Z. tritici did differ between B. distachyon and wheat. Our results suggest that phenylalanine ammonia lyase (PAL) expression may be important for NHR in B. distachyon while pathogenesis-related (PR) genes and expression of genes regulating reactive oxygen species (ROS) may be important to limit disease in wheat. Future studies of the B. distachyon-Z. tritici interaction may allow identification of conserved plant immunity targets which are responsible for the isolate specific responses observed in both plant species.

scholarly journals Two PR-1 Genes from Tomato Are Differentially Regulated and Reveal a Novel Mode of Expression for a Pathogenesis-Related Gene During the Hypersensitive Response and Development

1997 ◽  
Vol 10 (5) ◽  
pp. 624-634 ◽  
Author(s):  
Pablo Tornero ◽  
José Gadea ◽  
Vicente Conejero ◽  
Pablo Vera
Keyword(s):  
Expression Pattern ◽  
Hypersensitive Response ◽  
Constitutive Expression ◽  
Developmental Expression ◽  
Gus Gene ◽  
Cortical Cells ◽  
Pathogenesis Related ◽  
Genes Encoding ◽  
Refractory State ◽  
Pathogenesis Related Gene

Pathogenesis-related (PR) proteins form a heterogeneous family of plant proteins that are likely to be involved in defense and are inducible by pathogen attacks. One group of PRs, represented by the subfamily PR-1, are low-molecular-weight proteins of unknown biochemical function. Here we describe the cloning and characterization of two closely related genes encoding a basic and an acidic PR-1 protein (PR1b1 and PR1a2) from tomato (Lycopersicon esculentum). We present a comparative study of the mode of transcriptional regulation of these two genes in transgenic tobacco plants using a series of promoter-GUS fusions. Unexpectedly, the chimeric PR1a2/GUS gene is not induced by pathogenic signals but instead shows constitutive expression with a reproducible developmental expression pattern. It is expressed in shoot meristems, trichomes, and cortical cells as well as in vascular and nearby tissues of the mature stem. This constitutive expression pattern may represent preemption of plant defenses against potential pathogens. Conversely, the chimeric PR1b1/GUS gene does not show any constitutive expression in the plant, but it is transcriptionally activated following pathogen attack. Upon infection by tobacco mosaic virus, the PR1b1 gene is strongly activated locally in tissues undergoing the hypersensitive response but not systemically in uninoculated tissues. Furthermore, its expression is induced by both salicylic acid and ethylene precursors, two signals that coexist and apparently mediate the activation of local defenses during the hypersensitive response. We speculate that the different mode of expression of the two genes presented here, together with that reported previously for the induction of other PR-1 genes in systemic, uninoculated tissues, may all be complementary and necessary for the plant to acquire an efficient refractory state to resist pathogen attacks.

scholarly journals Seed-Specific Expression of Arabidopsis AtCYP85A2 Produces Biologically Active Brassinosteroids Such as Castasterone and Brassinolide to Improve Grain Yield and Quality in Seeds of Brachypodium Distachyon

2021 ◽  
Vol 12 ◽  
Author(s):  
Jeehee Roh ◽  
Jinyoung Moon ◽  
Ye Eun Lee ◽  
Chan Ho Park ◽  
Seong-Ki Kim
Keyword(s):  
Transgenic Plants ◽  
Grain Yield ◽  
Brachypodium Distachyon ◽  
Biologically Active ◽  
Wild Type Plant ◽  
Wild Type ◽  
Specific Expression ◽  
Yield And Quality ◽  
Grain Yield And Quality ◽  
Seed Specific Expression

Brachypodium distachyon is a monocotyledonous model plant that contains castasterone (CS) but no brassinolide (BL) as the end product of brassinosteroids (BR) biosynthesis, indicating dysfunction of BL synthase, which catalyzes the conversion of CS to BL. To increase BR activity, Arabidopsis cytochrome P450 85A2 (AtCYP85A2) encoding BR 6-oxidase/BL synthase was introduced into B. distachyon with the seed-specific promoters pBSU1, pAt5g10120, and pAt5g54000. RT-PCR analysis and GUS activity revealed that AtCYP85A2 was only expressed in the seeds of the transgenic plants pBSU1-AtCYP85A2::Bd21-3, pAt5g10120-AtCYP85A2::Bd21-3, and pAt5g54000-AtCYP85A2::Bd21-3. The crude enzyme prepared from the seeds of these three transgenic plants catalyzed the conversion of 6-deoxoCS to CS. The transgenic plants showed greater specific enzyme activity than the wild-type plant for the conversion of 6-deoxoCS to CS, indicating enhanced BR 6-oxidase activity in the transgenic plants. The enzyme solution also catalyzed the conversion of CS into BL. Additionally, BL was identified from the seeds of transgenic plants, verifying that seed-specific AtCYP85A2 encodes a functional BL synthase to increase BR activity in the seeds of transgenic Brachypodium. In comparison with wild-type Brachypodium, the transgenic plants showed better growth and development during the vegetative growing stage. The flowers of the transgenic plants were remarkably larger, resulting in increments in the number, size, and height of seeds. The total starch, protein, and lipid contents in transgenic plants were higher than those in wild-type plants, indicating that seed-specific expression of AtCYP85A2 improves both grain yield and quality in B. distachyon.

scholarly journals OsExo70B1 Positively Regulates Disease Resistance to Magnaporthe oryzae in Rice

2020 ◽  
Vol 21 (19) ◽  
pp. 7049
Author(s):  
Hongna Hou ◽  
Jianbo Fang ◽  
Jiahui Liang ◽  
Zhijuan Diao ◽  
Wei Wang ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Early Stage ◽  
Plant Immunity ◽  
Fungal Growth ◽  
Defense Responses ◽  
Pr Genes ◽  
Pathogenesis Related ◽  
Important Regulator ◽  
A Subunit ◽  
Molecular Patterns

The exocyst, an evolutionarily conserved octameric protein complex, mediates tethering of vesicles to the plasma membrane in the early stage of exocytosis. Arabidopsis Exo70, a subunit of the exocyst complex, has been found to be involved in plant immunity. Here, we characterize the function of OsExo70B1 in rice. OsExo70B1 mainly expresses in leaf and shoot and its expression is induced by pathogen-associated molecular patterns (PAMPs) and rice blast fungus Magnaporthe oryzae (M. oryzae). Knocking out OsExo70B1 results in significantly decreased resistance and defense responses to M. oryzae compared to the wild type, including more disease lesions and enhanced fungal growth, downregulated expression of pathogenesis-related (PR) genes, and decreased reactive oxygen species accumulation. In contrast, the exo70B1 mutant does not show any defects in growth and development. Furthermore, OsExo70B1 can interact with the receptor-like kinase OsCERK1, an essential component for chitin reception in rice. Taken together, our data demonstrate that OsExo70B1 functions as an important regulator in rice immunity.

scholarly journals The ATF/CREB Transcription Factor Atf1 Is Essential for Full Virulence, Deoxynivalenol Production, and Stress Tolerance in the Cereal Pathogen Fusarium graminearum

2013 ◽  
Vol 26 (12) ◽  
pp. 1378-1394 ◽  
Author(s):  
Thuat Van Nguyen ◽  
Cathrin Kröger ◽  
Jakob Bönnighausen ◽  
Wilhelm Schäfer ◽  
Jörg Bormann
Keyword(s):  
Transcription Factor ◽  
Osmotic Stress ◽  
Fusarium Graminearum ◽  
Brachypodium Distachyon ◽  
Constitutive Expression ◽  
Mitogen Activated Protein Kinase ◽  
Wild Type ◽  
Mitogen Activated Protein ◽  
In The Wild

Fusarium graminearum is a necrotrophic plant pathogen of cereals that produces mycotoxins such as deoxynivalenol (DON) and zearalenone (ZEA) in grains. The stress-activated mitogen-activated protein kinase FgOS-2 is a central regulator in F. graminearum and controls, among others, virulence and DON and ZEA production. Here, we characterized the ATF/CREB-activating transcription factor FgAtf1, a regulator that functions downstream of FgOS-2. We created deletion and overexpression mutants of Fgatf1, the latter being also in an FgOS-2 deletion mutant. FgAtf1 localizes to the nucleus and appears to interact with FgOS-2 under osmotic stress conditions. Deletion mutants in Fgatf1 (ΔFgatf1) are more sensitive to osmotic stress and less sensitive to oxidative stress compared with the wild type. Furthermore, sexual reproduction is delayed. ΔFgatf1 strains produced higher amounts of DON under in vitro induction conditions than that of the wild type. However, during wheat infection, DON production by ΔFgatf1 is strongly reduced. The ΔFgatf1 strains displayed strongly reduced virulence to wheat and maize. Interestingly, constitutive expression of Fgatf1 in the wild type led to hypervirulence on wheat, maize, and Brachypodium distachyon. Moreover, constitutive expression of Fgatf1 in the ΔFgOS-2 mutant background almost complements ΔFgOS-2-phenotypes. These data suggest that FgAtf1 may be the most important transcription factor regulated by FgOS-2.

scholarly journals Salicylic Acid Accumulation Controlled by LSD1 Is Essential in Triggering Cell Death in Response to Abiotic Stress

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 962
Author(s):  
Maciej Jerzy Bernacki ◽  
Anna Rusaczonek ◽  
Weronika Czarnocka ◽  
Stanisław Karpiński
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Abiotic Stress ◽  
Wild Type ◽  
Pr Genes ◽  
Genes Expression ◽  
Salicylic Acid Accumulation ◽  
Cell Death Phenotype ◽  
Insight Into

Salicylic acid (SA) is well known hormonal molecule involved in cell death regulation. In response to a broad range of environmental factors (e.g., high light, UV, pathogens attack), plants accumulate SA, which participates in cell death induction and spread in some foliar cells. LESION SIMULATING DISEASE 1 (LSD1) is one of the best-known cell death regulators in Arabidopsis thaliana. The lsd1 mutant, lacking functional LSD1 protein, accumulates SA and is conditionally susceptible to many biotic and abiotic stresses. In order to get more insight into the role of LSD1-dependent regulation of SA accumulation during cell death, we crossed the lsd1 with the sid2 mutant, caring mutation in ISOCHORISMATE SYNTHASE 1(ICS1) gene and having deregulated SA synthesis, and with plants expressing the bacterial nahG gene and thus decomposing SA to catechol. In response to UV A+B irradiation, the lsd1 mutant exhibited clear cell death phenotype, which was reversed in lsd1/sid2 and lsd1/NahG plants. The expression of PR-genes and the H2O2 content in UV-treated lsd1 were significantly higher when compared with the wild type. In contrast, lsd1/sid2 and lsd1/NahG plants demonstrated comparability with the wild-type level of PR-genes expression and H2O2. Our results demonstrate that SA accumulation is crucial for triggering cell death in lsd1, while the reduction of excessive SA accumulation may lead to a greater tolerance toward abiotic stress.

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